Is there a function that performs similar to 'accumarry' but multiplies instead of accumulates?

Hello all, Is there a function that performs similar to 'accumarry' but multiplies instead of accumulates? Thank you!

Answer 1

[Star Strider]

You can multiply with accumarray if you specify the prod function as the function you want it to use. This is an adaptation of a recent Answer that wanted to take the mean of values in the second column of the matrix that shared the same value of the first column, so I originally used the mean function. Here, I’m multiplying them instead, using the prod function:

ExCellArray = {[1 3.1; 2 4.5; 3 5.7; 4 8.2; 4 5.2]};
ExArray = cell2mat(ExCellArray);

[UExA, ia, ic] = unique(ExArray(:,1));

Out = [ExArray(ia,1) accumarray(ic, ExArray(:,2), [], @prod)]

Out =
            1          3.1
            2          4.5
            3          5.7
            4        42.64

The accumarray function can do a lot of neat stuff if you just ask it nicely!